GEOCHEMICAL JOURNAL
Online ISSN : 1880-5973
Print ISSN : 0016-7002
ISSN-L : 0016-7002
Search
Advanced search
OR
Browse
Search
Volume 13, Issue 6
Displaying 1-16 of 16 articles from this issue
Show all abstracts
    • |<
    • <
    • 1
    • >
    • >|
  • 326Ra in Bering Sea sediment and its application as a geochronometer
    Shizuo Tsunogai, Masatoshi Yamada
    1979 Volume 13 Issue 6 Pages 231-238
    Published: December 20, 1979
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.13.231
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    232Th, 230Th and 226Ra were determined for three pelagic cores collected in the northern North Pacific and the western and eastern basins of the Bering Sea. The surface sediment collected in the Pacific contains much 232Th and 230Th decreasing in concentration with depth indicating a sedimentation rate of 2.2 × 10-3 cm/yr. The Bering Sea sediments do not show vertical profiles of decreasing concentration with depth. This is due to a fast sedimentation rate in the Bering Sea. The excess radioactivity of 226Ra relative to that of 230Th was observed in the surface sediment collected in the eastern basin of the Bering Sea where the sediment was of siliceous ooze, showing a vertical profile decreasing in concentration with depth. The excess 226Ra is caused by the biogenic silicate material and has been used as a geochronometer. The sedimentation rate in the Bering Sea basin turns out to be 5 × 10-2cm/yr, which shows good agreement with that obtained by the 14C method. Therefore, 226Ra chronology is applicable to pelagic or hemi-pelagic sediment of siliceous ooze.
    View full abstract
    Download PDF (1912K)
  • Post depositional migration of Cu, Zn, Ni, Co, Pb and Ba in deep sea sediments
    Shizuo Tsunogai, Izumi Yonemaru, Masashi Kusakabe
    1979 Volume 13 Issue 6 Pages 239-252
    Published: December 20, 1979
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.13.239
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Sediment cores of various types were cut into sections each 2 to 10cm in length and analyzed for Cu, Zn, Ni, Co, Pb and Ba after chemical separation into acid soluble, reducible and refractory fractions. The results are compared with the data obtained for Mn. They proved the migration of Mn in pelagic sediment to have resulted from changes in redox conditions. Surface oxidizing sediment usually contains more of these transition metals than sediment from greater depths. Thus an excess portion of metals in the surface will be lost during early diagenesis. In some of the weakly oxidizing deep sediment transition metals as well as Mn are concentrated and the composition of the excess amounts is similar to that of the manganese nodules unless major components, such as silica and carbonate, are included. The deep layer enriched in transition metals is inferred to be diagenetically formed. In some sections of the deep reducing sediment, Mn is also concentrated in the acid soluble fraction, and may be precipitated as carbonate, but this layer does not contain large amounts of any other transition metals.
    View full abstract
    Download PDF (3392K)
  • Behavior of dissolved silica in parent solution at the formation of calcium carbonate
    Yasushi Kitano, Minoru Okumura, Masatoshi Idogaki
    1979 Volume 13 Issue 6 Pages 253-260
    Published: December 20, 1979
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.13.253
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    The authors have studied experimentally on the coprecipitation of dissolved silica with calcium carbonate (calcite or aragonite) and on the influence of silica dissolved in a parent calcium bicarbonate solution on the crystal form of calcium carbonate precipitated from the parent solution. The coprecipitation of dissolved silica with calcium carbonate is affected significantly by the crystal form of precipitated calcium carbonate and by the presence of sodium chloride in a parent solution. That is, dissolved silica is more easily coprecipitated with aragonite than with calcite. The presence of dissolved silica in a parent solution favors the formation of calcite and inhibits that of aragonite. The amounts of silica coprecipitated with calcite and also with aragonite increase with increasing concentration of sodium chloride, that is, with increasing value of ionic strength in the parent solution. This trend is observed at the coprecipitation of undissociated chemical species with calcium carbonate.
    View full abstract
    Download PDF (2150K)
  • Sulfur isotope ratios of some Japanese skarn deposits
    Hidehiko Shimazaki, Masahiro Yamamoto
    1979 Volume 13 Issue 6 Pages 261-268
    Published: December 20, 1979
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.13.261
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Sulfur isotope study of some Japanese skarn deposits of ilmenite-series granitoid affinity shows that sulfide minerals have δ34S values ranging from +0.7 to -12.2‰. The remarkable negative δ34S trend in the studied deposits gives support to an idea by SASAKI and ISHIHARA (in press) that there is a distinct parallelism between the sulfur isotopic data of rock sulfur and ore sulfur from magnetite and ilmenite-series of granitoids in Japan. δ34S values of 25 sulfide samples from the Tsumo mining area fall in a very narrow range from +0.7 to -1.7‰, irrespective of their various occurrences. δ34S values for sulfide sulfur of the Kawayama mine are negative and moderately large, suggesting contact metasomatic origin of the deposit. δ34S values of paired sulfide minerals are sometimes closer to each other than, or have in some cases reverse relation to, those expected from published experimental results.
    View full abstract
    Download PDF (2191K)
  • Isotopic composition of volcanic native sulfur from Japan
    Akira Ueda, Hitoshi Sakai, Akira Sasaki
    1979 Volume 13 Issue 6 Pages 269-275
    Published: December 20, 1979
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.13.269
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Some 140 native sulfur samples from 44 localities of Japan show a wide variation of δ34S(CDT) ranging from -9 to +7 ‰. Average δ34S value for the most representative native sulfur of this country is about -4‰. Distinct regional variation exists in the isotopic data. Native sulfur from West Japan tends to show greater δ34S values than from East Japan. This trend is likely to be correlated with the isotopic trend of the source volcanic gas system. However, whether or not the trend represents the isotopic variability in source magma is not clear at the moment.
    View full abstract
    Download PDF (1711K)
  • Distribution of cosmogenic chromium between alloys in an iron meteorite
    Seiichi Shibata, Masatake Honda
    1979 Volume 13 Issue 6 Pages 277-280
    Published: December 20, 1979
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.13.277
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    The distribution of the nuclear reaction product 51Cr between alloys in an iron meteorite was investigated by leaching with dilute sulfuric acid. The meteorite sample wrapped with a cadmium plate was irradiated with neutrons and cooled. The sample was leached and the γ rays from 51Cr, 54Mn, 58Co and 59Fe induced by 54Fe(n, α), 54Fe(n, p), 58Ni(n, p) and 58Fe(n, γ), respectively, were measured in each step of leaching. The chromium content was determined by atomic absorption spectroscopy (AAS) in each step. The Δ51Cr defined as the activity difference between the observed and calculated activities in each step was used for estimating the adsorption of the 51Cr onto the metal surface.
    View full abstract
    Download PDF (1156K)
  • Isotopic composition of gadolinium in meteorites
    P. K. Kuroda
    1979 Volume 13 Issue 6 Pages 281-285
    Published: December 20, 1979
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.13.281
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    An alternative explanation is presented for the neutron effects observed by EUGSTER et al. (1970) in Gd extracted from the Norton County achondrite. It is suggested that an ‘early’ irradiation of the solar system material occurred at a temperature much higher than 200°K assumed by the above investigators. It appears that the Gd anomalies are closely related to the O and Mg anomalies recently observed in various meteorites.
    View full abstract
    Download PDF (1400K)
  • More mysteries from Pandora's box?: Samarium isotopic anomalies in the Allende inclusions
    P. K. Kuroda
    1979 Volume 13 Issue 6 Pages 287-289
    Published: December 20, 1979
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.13.287
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    An alternative interpretation is presented for the Sm isotopic anomalies observed by MCCULLOCH et al. (1978) and LUGMAIR (1978) in the Allende mineral inclusions. The Allende inclusions appear to have received a smaller time-integrated neutron flux than the average earth material during an ‘early’ irradiation period.
    View full abstract
    Download PDF (585K)
  • Time scales inferred from the cosmochronometers iodine-129, plutonium-244 and aluminum-26
    P. K. Kuroda
    1979 Volume 13 Issue 6 Pages 291-295
    Published: December 20, 1979
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.13.291
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    The r-process-like isotopic anomalies observed in Ba, Nd, and Sm from the Allende inclusions EK1-4-1 and Cl can be explained as due to an ‘early’ irradiation of the solar system material, which also produced radionuclides such as 26Al, 107Pd and 129I. The apparent conflict between the time scales inferred from the cosmochronometers 119I, 244Pu and 26Al reported by LEE et al. (1978) stems from the fact that these investigators have attempted to explain the isotopic anomalies in terms of a wholesale addition of the nucleosynthesis products from nearby stars to the solar nebula.
    View full abstract
    Download PDF (1257K)
  • Correlated calcium and titanium isotopic anomalies in Allende inclusions
    P. K. Kuroda
    1979 Volume 13 Issue 6 Pages 297-300
    Published: December 20, 1979
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.13.297
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    The isotopic anomalies recently observed in Ca(Z=20) and Ti(Z=22) in the Allende inclusions are related to each other and can be explained as due to a combined effect of mass-fractionation and cosmic-ray irradiation processes which occurred during the early history of the solar system.
    View full abstract
    Download PDF (989K)
  • Growth rate of terrestrial ferro-manganese nodules in the limestone area of the Ryukyu Islands
    Hatsuo Taira, Yasushi Kitano, Kiyoshi Kaneshima
    1979 Volume 13 Issue 6 Pages 301-305
    Published: December 20, 1979
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.13.301
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    The growth rate of terrestrial ferro-manganese nodules formed in limestone areas of the Ryukyu Islands has been determined by a radiochemical method. The ionium-thorium ratios exponentially decrease with depth from the surface of the manganese nodule, and the growth rate has been evaluated as (61 ± 9)mm per 106 years for samples collected from a reddish soil accumulated on the stratum of Naha Limestone at Nakijin-son, the northern part of Okinawa-jima. The growth rate will lead to the age of (16 ± 2) × 104 years for a manganese nodule about 2.0cm in diameter, which is of the largest size in the area. This may give an estimation of the upper limit age for the Riukiu (Naha) Limestone formation.
    View full abstract
    Download PDF (1621K)
  • Direct measurements of D/H and 18O/16O fractionation factors between vapor and liquid water in the temperature range from 10 to 40°C
    Masahisa Kakiuchi, Sadao Matsuo
    1979 Volume 13 Issue 6 Pages 307-311
    Published: December 20, 1979
    Released on J-STAGE: April 08, 2008
    DOIhttps://doi.org/10.2343/geochemj.13.307
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Vapor phase was separately collected without liquid condensate by raising the temperature of the container of vapor phase by 7°C higher than that of the interface of vapor-liquid equilibrium. D/H and 18O/16O measurements were done for the identical aliquot of vapor samples in equilibrium with the liquid water in the temperature range from 10 to 40°C. The empirical relationships between αD, α18O and the temperature of equilibration were obtained to be, 103lnαD = 2.408 × 106T-2 + 6.455 × 104T-1 - 168.7, 103lnα18O = 5.9702 × 106T-2 - 3.2801 × 104T-1 + 52.227.
    View full abstract
    Download PDF (1142K)
  • ERRATA
    1979 Volume 13 Issue 6 Pages e2a
    Published: 1979
    Released on J-STAGE: February 06, 2009
    DOIhttps://doi.org/10.2343/geochemj.13.e2a
    JOURNAL FREE ACCESS
    Download PDF (620K)
  • ERRATA
    1979 Volume 13 Issue 6 Pages e2b
    Published: 1979
    Released on J-STAGE: February 06, 2009
    DOIhttps://doi.org/10.2343/geochemj.13.e2b
    JOURNAL FREE ACCESS
    Download PDF (620K)
  • ERRATA
    1979 Volume 13 Issue 6 Pages e2c
    Published: 1979
    Released on J-STAGE: February 06, 2009
    DOIhttps://doi.org/10.2343/geochemj.13.e2c
    JOURNAL FREE ACCESS
    Download PDF (620K)
  • ERRATA
    1979 Volume 13 Issue 6 Pages e2d
    Published: 1979
    Released on J-STAGE: February 06, 2009
    DOIhttps://doi.org/10.2343/geochemj.13.e2d
    JOURNAL FREE ACCESS
    Download PDF (620K)
    • |<
    • <
    • 1
    • >
    • >|
feedback
 Top